The present invention is concerned with a flushing device for a water closet incorporating a bowl. Very much and often expensive drinking water is used every day worldwide to flush water closets. For many years, extensive research has therefore been conducted in an attempt to reduce the amount of water consumed for the flushing of water closets. A significant contribution to this has been made with flush tanks that have an interruptible flush or a selectively activated partial flush. With the partial flush significantly less water is used for flushing after a small job than usual. Also known are flushing devices in which water is accelerated by means of a water nozzle during the flushing process in the siphon. A flushing device of this type is revealed, for instance, in the applicant""s WO 95/04196. However, even here the minimum water consumption is at least three liters and the operative complexity is comparatively high. The pressure flushing device according to EP-A-0 352 712 operates in a similar manner.
Flushing devices are furthermore known in which water is suctioned out of the siphon of the water closet during flushing by means of a vacuum pump and a suction line. In railway cars, toilets are known that have a basin with an opening and a shutter below the same that can be swiveled off to the side. Since no effective odor closure is present here and none is needed, these toilets are not suitable for in-home use. Lastly, water closets are known in which the excreta are burned, composted or packaged. These water closets work without a flushing device and have so far proven useful only for special applications, for example in vehicles or on campgrounds. However, in the known flushing devices a shortcoming is presented not only by the high water consumption but also by the generated noise. The ideal flushing device would, therefore, operate without water and noiseless and would, furthermore, be germproof The invention now has as its object to create a flushing device of the above class that comes closer to this ideal design than the flushing devices that are known so far.
The object of the invention is met with a flushing device according to the preamble as per claim 1. In the inventive flushing device provision is thus made for a flushing module to be disposed in the excrement catch area of the bowl. In the inventive device, the flushing, in principle, thereby no longer takes place from the top, as until now, but from the bottom and with a module to be affixed to the underside of the bowl. It is now an essential feature that this prevents the previously unavoidable high energy loss due to friction of the flushing water in the flush tank, in the drain bend and in the bowl. The flushing water can be used directly and with less energy loss in the flushing module. Also avoided is the generation of noise in the flush tank, in the drain pipe and in the bowl. Since the flushing takes place underneath the bowl, in the module, the generation of noise can be dampened significantly more effectively than before.
It is also regarded as a significant aspect of the invention that the installation can be significantly simplified. This is based on the fact that the current multiple interfaces between the water closet and the building can often be reduced only by using a plug-in interface. The flushing module is mounted on the building floor by means of a mounting plate, for example, and the toilet bowl is subsequently fixed on the same.
In a further development of the invention, the flushing module has, at an upper end, a first catch area to receive flushing water and excreta, and means are provided by which the catch area can be emptied into a space disposed below the same. The excreta fall into this first catch area and are subsequently emptied into a space disposed below the same, for example into a collection container. The emptying is particularly effective if this takes place by a swiveling or tilting away. The swiveling away takes place, according to a further development of the invention, by rotating the catch area. The emptying thus takes place in a manner similar to known ashtrays in which a catch plate is rotated when a button is pressed, resulting in the ashes to be hurled away radially. The excreta then leave the catch area together with the flushing water that is present in this catch area. The emptying is particularly effective if a downward movement of the catch area occurs simultaneously with a rotation. A hydraulic drive is preferably provided for both movements. This becomes particularly simple and cost-effective from a design point of view if the catch area is connected to a hydraulic cylinder. By moving the piston of the cylinder, the catch area is then moved downward. Suitable guide means simultaneously exert a rotating movement onto the catch area during this downward movement.
In a further development, provision is made for the flushing module to form, together with a portion of the bowl disposed at a distance to the former, an odor trap in such a way that a space between the flushing module and this portion is filled with water. In this manner, an odor trap is formed that is very easy to build and cost-effective, as well as reliable. When the catch area is refilled with flushing water after a flush, this odor trap takes effect immediately and prevents odors from passing from the interior of the module into the bowl. It is now an essential feature that an odor trap of this type requires comparatively little water.
A particularly effective cleaning results when, according to a further development of the invention, nozzle openings are disposed approximately centrically in the catch area, through which flushing water can be sprayed radially outward. The emptying of the catch area is thus supported by the flushing water exiting through the nozzle openings. This exiting of this flushing water may be actuated by a downward movement of the catch area.
If, according to a further development of the invention, refining means are disposed underneath the catch area in said compartment, whereby feces may, for example, be reduced mechanically, the excreta can be collected in a second catch area in the form of a thick liquid. This area with the refining means can preferably be cleaned with high-pressure or steam nozzles and is can be1 hermetically sealed on the bottom toward the sewer line.
1 Translator""s note: the German-language sentence on which this translation is based contains either a grammatical error or superfluous words. 
For installation purposes, the flushing module is preferably fixed as an entire unit on a standard interface plate with a quick lock. Located on this plate are the drain, a compressed water connection, as well as preferably also a power supply connection. The WC bowl can now be plugged onto the interface without additional installation costs and is immediately operable.
The invention is also concerned with a method for flushing a water closet. In this method the excreta are collected in a catch area that is disposed in a lower region of a toilet bowl and at least partly filled with water, and subsequently emptied from this area into a further area located underneath. As in the device, the underlying concept that the excreta are collected in a catch area and subsequently flushed there is an essential feature in the inventive method as well.
Further advantageous characteristics will become apparent from the dependent claims, from the following description and from the drawings.